In order to achieve advanced miniaturization of devices such as semiconductor devices, it is necessary to form a pattern having a smaller dimension than a critical dimension obtained by microprocessing with the conventional photolithography. As one of methods for forming such a pattern, EUV (Extreme Ultraviolet), which is a next-generation exposure technology, is under development. A wavelength of a EUV light source is remarkably shorter than a wavelength of a conventional UV light source, and for example, a very short wavelength of 13.5 nm is used. Accordingly, in the EUV, there is a technical barrier to mass production, and a problem such as a longer exposure time is yet to be solved. Therefore, it is required to develop a method of manufacturing a further miniaturized device.
For this purpose, a technology for forming a pattern using a self-assembled block copolymer (BCP) as one of self-assembled materials capable of forming organized patterns by themselves has attracted attention. Such a technology is described in Patent Documents 1 and 2.
In Patent Document 1, a block copolymer layer, which includes a block copolymer containing at least two polymer block components A and B that are not mixed with each other, is coated on an underlying layer. Thereafter, a heat-treatment (annealing) is performed in order to phase-separate the polymer block components A and B by themselves. Thus, an organized pattern including a first region containing the polymer block component A and a second region containing the second polymer block component B can be obtained. Further, in Patent Document 2, as a method of forming a via, there is proposed a processing of patterning a block copolymer. According to the patterning processing described in Patent Document 2, in a first region and a second region of a phase-separated block copolymer layer, the second region is removed between the first region and the second region, so that a pattern can be obtained.
A dimension of the pattern obtained by patterning a block copolymer layer described in Patent Documents 1 and 2 is typically within 10 nm which has been very difficult to achieve in the conventional photolithography.
Patent Document 1: Japanese Patent Laid-open Publication No. 2007-208255
Patent Document 2: Japanese Patent Laid-open Publication No. 2010-269304